There are two commonly known seed storage proteins in the cultivated common bean, Phaseolus vulqaris: phytohemagglutinin (PHA, also referred to as bean lectin) and phaseolin. Recently, wild forms of Phaseolus vulqaris L., indigenous to Middle and South America, have been found to contain a novel family of proteins previously unreported in the common bean. These proteins, named arcelins, have subunit molecular weights similar to lectin proteins or intermediate to phaseolin and lectin proteins, and occur in the globulin-2 protein fraction. Four electrophoretic variants, or isoproteins, have been observed and designated arcelin-1, -2, -3 and -4. See Romero Andreas et al. (1986) Theor Appl. Genet. 72:123-128; Osborn et al. (1986) Theor. Appl. Genet. 71:847-855.
The presence of arcelin in wild beans has been correlated with resistance to two bruchid beetle species. It is not known, however, whether this resistance is attributable to arcelin in whole, or even in part. See Osborn et al, supra; Schoonhoven et al. (1983) J. Econ. Entomol. 76:1255-1259.
Other seed storage proteins have been cloned and expressed in heterologous plants. For example, a sample for phaseolin protein from Phaseolus vulgaris (French bean) has been cloned and expressed in heterologous plants under the control of its own promoter and heterologous promoters. See, e.g., Murai et al. (1984) Science 222:476; Segupta-Gopalan et al. (1985) Proc. Natl. Acad. Sci, USA 82:3320; EPO Pub. No. 126,546; EPO Pub. No. 122,791. Heterologous plants have also been transformed by the gene for the corn storage protein, zein. Matzke et al. (1984) EMBO J. 3:1525-1531; Messing in Genetic Engineering 6:1-46 (W. J. Rigby ed. 1987). The Brazil nut 2S storage protein has also been expressed in heterologous plants. See copending U.S. Pat. App. Ser. No. 065,303, filed Jun. 19, 1987.